Does that mean that you can have an ide raid array(i.e. wouldn't have to buy satas?)
I want to have two drives as mirrors of each other, but i don't want to have to buy new drives(i have an eide ata100 160 gig and an ultra ata100 80 gig)
I wondered if i could partition the 160 into two equal sections and have the second drive mirror the first have of the 160. is it possible to have an array consisting of two partitions? maybe a silly question.
thanks
dan

It is possible to have an IDE RAID... defined through software. Both Windoze and Linux will allow you to do it, and I bet that Mac OS X will too (I do not have a Mac OS X to test it on, but the stuff is there).

You can have the two drives (the 160 GB, and the 80 gig) Mirror (RAID 1) each other, as long as the partition on the 160 GB is made equal to the partion size of the 80 GB. Be sure to research out the exact sizes.

It is possible to do what you are suggesting. I have seen it done... but I would suggest that you have different IDE controllers involved for max performance, and that you do not have the other half of the 160 being very busy... or you will loose performance. Perhaps have the back half of the drive used for backups.

Thanks for the info!
one question leads to another:
you said you could have a raid array defined by software. does that mean that you don't need the onboard system? just trying to visualize how that would work.

also I noticed a wide variety of prices for controllers. what should i look for in a controller? How slow would you expect the onboard system to be? would it be better than a cheap controller?

by the way the 80 gig drive shows as 74.5 gigs in my computer. would i need to drop to 70 gigs or could i use the full 74.5? sorry for all of the questions.
thanks for the info
dan

Thanks for the info!
one question leads to another:
you said you could have a raid array defined by software. does that mean that you don't need the onboard system? just trying to visualize how that would work.

also I noticed a wide variety of prices for controllers. what should i look for in a controller? How slow would you expect the onboard system to be? would it be better than a cheap controller?

by the way the 80 gig drive shows as 74.5 gigs in my computer. would i need to drop to 70 gigs or could i use the full 74.5? sorry for all of the questions.
thanks for the info
dan

Windows XP Pro, Windows 2000, Linux, and the *BSDs all support "Logical Volumes", meaning you could do just like you're asking about. It's software based, and you don't need a dedicated controller to do it. Just follow kc0arf's advice and ensure the partitions are exactly the same size.

You can do it but I would strongly suggest that you only use identical drives.

Different cyl, hd, sec layouts and access times is just looking for a potential problem of the worst kind. I have been running IDE raids since they came out.... Both onboard as well as add in cards... Al least try the onboard IDE Raid before dismissing it.. True they are just like any other onboard product (not as good as a premium add on) but some of them work quite well.